I installed the Ubuntu 16.04 desktop version on a machine, and used it for my research via ssh.
Sometimes the machine restarts randomly, but I cannot find why restart.
$ last reboot
reboot system boot 4.4.0-62-generic Wed Feb 8 01:34 still running
reboot system boot 4.4.0-62-generic Mon Feb 6 09:16 still running
reboot system boot 4.4.0-62-generic Sun Feb 5 16:43 still running
reboot system boot 4.4.0-62-generic Sun Feb 5 00:37 still running
I checked /var/log/syslog
...
Feb 7 23:31:37 niaserver7 systemd[1]: Started Session 77 of user swmo.
Feb 8 00:17:01 niaserver7 CRON[17883]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Feb 8 00:34:07 niaserver7 systemd[1]: Started CUPS Scheduler.
Feb 8 01:17:01 niaserver7 CRON[17893]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Feb 8 01:35:01 niaserver7 rsyslogd: [origin software="rsyslogd" swVersion="8.16.0" x-pid="1315" x-info="http://www.rsyslog.com"] start
Feb 8 01:35:01 niaserver7 systemd-modules-load[538]: Inserted module 'lp'
Feb 8 01:35:01 niaserver7 systemd-modules-load[538]: Inserted module 'ppdev'
Feb 8 01:35:01 niaserver7 kernel: [ 0.000000] Initializing cgroup subsys cpuset
Feb 8 01:35:01 niaserver7 rsyslogd-2222: command 'KLogPermitNonKernelFacility' is currently not permitted - did you already set it via a RainerScript command (v6+ config)? [v8.16.0 try http://www.rsyslog.com/e/2222 ]
Feb 8 01:35:01 niaserver7 systemd-modules-load[538]: Inserted module 'parport_pc'
Feb 8 01:35:01 niaserver7 rsyslogd: rsyslogd's groupid changed to 108
Feb 8 01:35:01 niaserver7 rsyslogd: rsyslogd's userid changed to 104
Feb 8 01:35:01 niaserver7 loadkeys[541]: Loading /etc/console-setup/cached.kmap.gz
Feb 8 01:35:01 niaserver7 kernel: [ 0.000000] Initializing cgroup subsys cpu
Feb 8 01:35:01 niaserver7 systemd[1]: Started udev Kernel Device Manager.
How can I fix it?